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ABAP Keyword Documentation →  ABAP - Reference →  Program Flow Logic →  Expressions and Functions for Conditions →  log_exp - Logical Expressions →  rel_exp - Predicates →  rel_exp - Predicate Functions →  Predicate Functions for Table-Like Arguments 

rel_exp - line_exists, Predicate Function

Other versions: 7.31 | 7.40 | 7.54

Syntax


... line_exists( table_exp ) ...

Effect

The predicate function line_exists checks whether the row of an internal table specified in the table expression table_exp exists and returns the appropriate logical value. Alongside single table expressions, table_exp can also handle chainings, whose result is a row of an internal table.

Within line_exists, an explicitly specified table key in the table row table_line of the table expression is handled in the same way as a free search key specified for this table key.


Notes

  • The table expression is only used to check the existence of the specified row. No temporary result is created.

  • The predicate function line_exists can be considered as a short form of the statement READ TABLE with the addition TRANSPORTING NO FIELDS following by sy-subrc being checked.

  • The predicate function line_exists cannot be used to determine the row number in a table index of a search key, since table expressions do not fill the system field sy-tabix. The table function line_index can be used instead.

  • If a search key specified in table_line in the table expression covers the initial part of a secondary table key without being specified explicitly after KEY, a syntax check warning is produced (which can be hidden by a pragma), since the function is generally quicker if the secondary key is specified explicitly.

  • As in other use cases for table expressions, line_exists must be used carefully and no duplicate selections made. For example, line_exists should not be used to first check the existence of row and then read it. Instead, the table expression can be assigned to a field symbol and then sy-subrc checked. If the row in question usually exists, the table expression can be specified in the required operand position and the exception CX_SY_ITAB_LINE_NOT_FOUND caught.

  • As well as assigning a table expression a default value for rows that are not found, there is also the option of checking the existences of rows.


Example

DATA flight_tab TYPE HASHED TABLE OF spfli 
                     WITH UNIQUE KEY carrid connid. 

SELECT * 
       FROM spfli 
       INTO TABLE @flight_tab. 

IF line_exists( flight_tab[ carrid = 'LH' 
                           connid = '0400' ] ). 
  ... 
ENDIF.